Gravity is a natural phenomenon by which all things with mass are brought toward one another. All forms of energy, including light, also cause gravitation and are under the influence of it. Gravity has an infinite range.
Gravity is most accurately described, not as a force, but as a consequence of the curvature of spacetime. The most extreme example of this curvature of spacetime is a black hole, from which nothing can escape once past its event horizon, not even light